Dielectric loss tand and partial discharge (PD) are important indicators for status assessment of oil-pressboard insulation. The correlation characteristics between these two parameters has significance for understanding the material’s degradation and helps to eliminate the information asymmetry for diagnostics. In this paper, the symmetric experimental platform is set up to measure the dielectric loss tand and PD for oil-pressboard insulation following the designed testing procedure consisted of raised and rested voltages. Three sets of samples with different water content were tested. The variation mechanism of tand with voltage is explained by proposed equivalent circuit, which introduced an asymmetric component representing defect part. PDs are found to be symmetric in the sinusoidal voltage cycles and their statistical parameters are calculated. Besides, the correlation between dielectric loss difference from raised voltage to rested voltage and PD is researched. Strong correlation is observed between dielectric loss and PD, which offers degradation insight for oil-pressboard insulation and helps to eliminate information asymmetry for material status diagnostics.

中文翻译：

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石油绝缘板介电损耗与局部放电的相关性

介电损耗和局部放电（PD）是评估油压板绝缘状态的重要指标。这两个参数之间的相关特性对于理解材料的降解具有重要意义，并有助于消除诊断中的信息不对称性。在本文中，按照设计的由升高和静止电压组成的测试程序，建立了对称的实验平台，以测量油压板绝缘的介电损耗线和PD。测试了三组水含量不同的样品。通过提出的等效电路解释了串联电压随电压的变化机理，引入了代表缺陷部分的不对称分量。发现PD在正弦电压周期中是对称的，并计算了它们的统计参数。此外，研究了从升高电压到静止电压的介电损耗差与PD之间的关系。在介电损耗和PD之间观察到强相关性，这为油压板绝缘提供了退化的见解，并有助于消除信息不对称性以进行材料状态诊断。